The present invention relates to a device, especially autonomous and portable, for extracting heat from a hot source.
The invention has been developed in the course of research intended for providing the protection of personnel operating in protective suits in a toxic environment with very high temperature conditions. For example such conditions arise while fighting fires or while working in a polluted medium. In this case, the person is equipped with a protective suit which protects him effectively against toxic substances and against external heat, but the internal heat originating from the body of the operator himself cannot be removed, so that the temperature inside the protective suit can rise to levels which exceed acceptable limits. A continuous connection between the inside of the protective suit and a coupling source, which is not transportable by the wearer, is not desirable as it eliminates the autonomy of the protective suit. A heat accumulator can form an autonomous cold source.
The invention is also applicable to a spacesuit for extra-vehicular activity where the removal of metabolic heat from the astronaut arises in the same manner.
The invention can also find applications in cases where it is essential to ensure that equipment or articles, for example biological specimens, should have a temperature which remains within fixed limits, even in the event of a momentary interruption in the communication with an energy source.
In order to solve this problem, it springs to mind completely naturally to use substances known in refrigerating systems, for example carbon dioxide or compounds of the "Freon" family. However, these commonly used substances essentially absorb heat by passing from the solid or liquid state to the gaseous state. This change of state corresponds to a very large volume change, and results in very bulky materials or in the necessity of a supply of mechanical energy (refrigerators).
It would be possible to imagine making the gaseous phase escape into the atmosphere, in particular in the case of carbon dioxide, but that can lead to a considerable increase in the cost and in the complexity of the apparatus for reconditioning the accumulator, as well as to the emission of reactive or toxic vapours.